EP1346667A1 - Method of adjustment of a base structure for a bed or the like - Google Patents

Abstract

An adjusting action control system (4) for a base structure (3) for a bed (1) or the like characterizedin that when the support portions (3a,3b,3c) of the base structure (3) are adjusted to desired positions, anadjusting action pattern can be preset to act until the support portions (3a,3b,3c) reach the desiredpositions.

Description

• The present invention relates to a method of controlling the adjustment of a base structurefor a bed or the like. More particularly, the present invention relates to a method ofcontrolling the adjustment of a base structure for a bed or the like which allows acoordinative action pattern to be preset so that when the support portions of the basestructure for a bed or the like are adjusted to desired positions, the adjusting action can becarried out according to a desired coordinative action pattern.
• As used in this specification, the term "bed or the like" will be understood to includehospital beds, ICU beds, long-term care beds, hospital trolleys, operating tables,stretchers and any other structure incorporating a horizontal surface on which a user maylie.
• At present, the position adjusting functions for support portions of a base structure for abed or the like include such functions as adjusting the inclinations of support portions(such as the back-support portion and the leg-support portion), adjusting the heights ofthe support portions, adjusting the expansion and contraction, and rolling. Thesefunctions are actuated based on the control commands issued from remote controlswitches or control switches mounted on a control panel operated by an attendant, nurseor the like, to bring the support portions to respectively desired positions.
• However, the above-mentioned functions of a bed or the like are usually merely carriedout according to an action pattern preset when the bed or the like is produced.
• So, for example in the case where back lifting only is carried out, a forward sliding forceacts from the mattress on the back-support portion to the upper half of the body of asubject lying thereon, to press on the abdominal region of the subject. To prevent thisfeeling of pressure and the forward sliding movement of the subject during back lifting, itis proposed to operate the back-support portion and the leg-support portion in ancoordinated manner. However, if back lifting and knee lifting are operated in ancoordinated manner according to a predetermined action pattern from the beginning, it isnot possible to stop knee lifting only halfway or to move the support portions in such amanner as to deviate from the action pattern, thereby reducing the effect of inhibition ofthe feeling of abdominal region pressure experienced by the subject and the forwardsliding movement of the subject during the aforementioned back lifting.
• The present invention seeks to address the above-mentioned problem. The object of thisinvention is to provide an adjusting action control system base structure for a bed or thelike, in which when the support portions of the bed or the like are adjusted to desiredpositions, a coordinative action pattern can be preset to allow the adjusting actionaccording to the desired coordinative action pattern.
• According to a first aspect of the present invention there is provided an adjusting actioncontrol system for a base structure for a bed or the like, characterized in that when thesupport portions of the base structure are adjusted to desired positions, an adjusting action pattern can be preset to act until the support portions reach the desired positions.
• A second aspect of the present invention provides an adjusting action control system for abase structure for a bed or the like, characterized in that when a back-support portion islifted and lowered, a coordinative action pattern can be preset for the back lifting andlowering and accompanying knee lifting and lowering of a subject lying thereon until aback lifting angle of the back-support portion is reached.
• A third aspect of the present invention provides an adjusting action control system for abase structure for a bed or the like, characterized in that when the lifting of theback-support portion and the lifting of the leg-support portion of the base structure areadjusted, a coordinative action pattern can be preset to act until the desired positions ofthe support portions are reached.
• Preferably, in an adjusting action control system according to the present invention,wherein the time difference between the time instant of starting the knee lifting of theleg-support portion and the time instant of starting the back lifting of the back bottomsection, and a knee lifting time period of the knee bottom section, are preset in acoordinative action pattern for the back lifting of the back-support portion, wherein theknee lifting of the leg-support portion is started first; subsequently after lapse of saidpreset time difference, the back lifting of the back-support portion is started; and afterlapse of said preset knee lifting time period of the knee bottom section, the knee lifting ofthe leg-support portion is stopped and then the knee lowering of the leg-support portion isstarted, while the back lifting of the back-support portion is continued until a desired back lifting angle is reached.
• Alternatively, in an adjusting action control system according to the present invention,wherein the time difference between the time instant of starting the knee lifting of theleg-support portion and the time instant of starting the back lifting of the back-supportportion, and a knee lifting angle of the leg-support portion, are preset in a coordinativeaction pattern for adjusting the back lifting and knee lifting of the respective supportportions, wherein the lifting of the leg-support portion is started first; subsequently afterlapse of said preset time difference, the back lifting of the back-support portion is started;and if the leg-support portion reaches the preset knee lifting angle, the knee lifting of theleg-support portion is stopped, while the back lifting of the back-support portion iscontinued until a predetermined back lifting angle is reached.
• In a control system according to a first aspect of the present invention, when the supportportions of a bed or the like are adjusted to desired positions, they may be adjustedaccording to a desired adjusting action pattern. Thus, the support portions can beadjusted to suit the lying person.
• In a control system according to a second aspect of the present invention, when theback-support portion of a bed or the like is lifted and lowered, the lifting and loweringmay be carried out according to a preset coordinative action pattern accompanying thelifting and lowering of the knee bottom section. Therefore, the lifting and lowering ofthe back-support portion can be adjusted to reduce the forward sliding of a subject lyingthereon and to reduce the feelings of discomfort of the subject due to compression of the abdominal region.
• In a control system according to a third aspect of the present invention, when the backlifting and knee lifting of the respective support portions of a base structure for a bed orthe like are adjusted, the adjustment may be carried out according to a coordinative actionpattern suitable for the subject lying thereon.
• According to a second aspect of the invention, since the time difference between the timeinstant of starting the knee lifting of the leg-support portion and the time instant ofstarting the back lifting of the back-support portion, and a knee lifting time period of theleg-support portion, are preset, the coordinative action pattern for the back lifting of theback-support portion may be newly set.
• In a control system according to a third aspect of the present invention, preferably, thetime difference between the time instant of starting the knee lifting of the leg-supportportion and the time instant of starting the back lifting of the back-support portion, and aknee lifting angle of the leg-support portion, are preset in a coordinative action pattern foradjusting the back lifting and knee lifting of the respective support portions.
• Figure 1 is a side view showing a section of a bed apparatus for carrying out theadjusting action control system in accordance with the present invention
• Figure 2 is a block diagram for illustrating the adjusting action control system inthe bed apparatus shown in Figure 3.
• Figure 3 is a graph showing an example of the coordinative action pattern preset in the adjusting action control system of Figure 1
• Figure 4 is a side view of a section showing the entire form of a base structure ina state where all the support portions are kept down to lie flat in a non-raised position.
• Figure 5 to 9 are side views of sections showing the entire form of a basestructure in various phases in the lifting action, in the case where the method ofcontrolling the coordinative lifting of support portions in accordance with the presentinvention is applied to a base structure for a bed.
• Figure 1 shows abed apparatus 1. In thebed apparatus 1, abase structure 3 placed on abed frame 2 is divided into a back-support portion 3a corresponding to the back of asubject lying thereon, a leg-support portion 3b corresponding to the region from the waistto the knees of a subject lying thereon and a lower-leg-support portion 3c correspondingto the legs of a subject lying thereon. Though not illustrated, a back lifting link as a backlifting mechanism abuts the back side of said back-support portion 3a, while a knee liftinglink as a knee lifting mechanism is attached to the back side of the leg-support portion 3bfor lifting and lowering the leg-support portion 3b and theleg bottom section 3c in ancoordinative manner. The back lifting link and the knee lifting link are respectivelyconnected to drive means (described later), for allowing back lifting and knee lifting.
• That is, the back lifting mechanism of the back-support portion 3a and the knee liftingmechanism of the leg-support portion 3b of thebed apparatus 1 are actuated by means ofan adjustingaction control system 4, for allowing back lifting, knee lifting and thecoordinative action of back lifting and lowering and knee lifting and lowering.
• Said adjustingaction control system 4 is described below.
• In the adjustingaction control system 4, the control switches (described later) mounted onacontrol panel 6 for giving control commands, installed on the outer surface of afootboard 5 are operated to give action command signals to acontroller 7 mounted on acontrol box (not illustrated) placed on thebed frame 2, and controlled action power issupplied from thecontroller 7 to themotors 8a and 8b functioning as drive sources of theback lifting mechanism and the knee lifting mechanism, for starting themotors 8a and 8b.Thecontroller 7 obtains the position information of the respective support portions fromthe action detecting means (not illustrated) of themotors 8a and 8b. Furthermore, thecontroller 7 of the bottom adjustingaction control system 4 has a storing means 9mounted for storing the coordinative action pattern of thebase structure 3 described later.
• Thecontrol panel 6 installed on the outer surface of thefootboard 5 is described below.As shown in Fig. 2, thecontrol panel 6 has control switches for back lifting and lowering,knee lifting and lowering and coordinative action of back lifting and lowering and kneelifting and lowering, i.e., head lifting switch Sw1, head lowering switch Sw2, leg liftingswitch Sw3, leg lowering switch Sw4, back lifting and knee lifting coordinative switchSw5 and back lowering and knee lowering coordinative switch Sw6.
• Thecontrol panel 6 also has a time difference setting switch St for presetting the timedifference (t) between the time instant of starting the back lifting of the back-supportportion 3a and the time instant of starting the knee lifting of the leg-support portion 3b,and an angle setting switch Sa for presetting the knee lifting angle a for presetting a bottom coordinative action pattern, for example, as shown in Fig. 3.
• The time difference (t) and the knee lifting angle a respectively preset by the timedifference setting switch St and the angle setting switch Sa are stored in the storing means9 in thecontroller 7, and based on the data stored as a newly preset action pattern, theback-support portion 3a and the leg-support portion 3b are operated in an coordinativemanner.
• Furthermore, thecontroller 7 has the following control procedures preset in it:
     As switching for back lifting, knee lifting is started (the knee lifting motor isturned on for normal rotation), and after lapse of time t, back lifting is started (the backlifting motor is turned on for normal rotation). If the knee lifting angle a reaches thepreset angle, knee lifting is stopped (the knee lifting motor is turned off), and kneelowering is started (the knee lifting motor is turned on for reverse rotation). The timedifference t is set by means of the time difference setting switch St, and the knee liftingangle a is set by means of the angle setting switch Sa.
     For switching for gatch action (concurrent back lifting and knee lifting), kneelifting is started (the knee lifting motor is turned on for normal rotation), and after lapse oftime t, back lifting is started (the back lifting motor is turned on for normal rotation). Ifthe knee lifting angle a reaches the preset angle, knee lifting is stopped (the knee liftingmotor is turned off).
• The back lifting angle of the back-support portion 3a is set for limiting the angle formedbetween the back-support portion 3a and the leg-support portion 3b, for example, at 90° or more.
• Since the back lifting speed and the knee lifting speed are constant when the electricpower to the motors is constant, the knee lifting angle a can also be preset as apredetermined time period T based on the relation.
• Themotors 8a and 8b respectively have, for example, adequate rotation quantitydetecting means (not illustrated) for identifying the present state of the support portions,i.e., the position information with reference to the rotation quantities of the motors. Thesignals detected by the rotation quantity detecting means are sent as position informationto thecontroller 7, and further to thecontrol panel 6, and are displayed, for example, by adisplay means (LEDs, etc.) for letting the operator recognize as the position informationof the bottom sections.
• According to the bottom adjustingaction control system 4 described above, when theback lifting of the back-support portion 3a is carried out, since a coordinative actionpattern accompanying the action of the leg-support portion 3b is used, the back lifting canbe adjusted with the forward sliding of the subject and the feelings of abdominal regioncompression felt by the subject are minimized.
• In this case, the knee lifting angle a at which abdominal compression discomfort is felt isdifferent from subject to subject, and the body weight is also different from subject tosubject. Since the loads acting on themotors 8a and 8b are different, the back liftingspeed and the knee lifting speed also become different. So, if the time difference setting switch St for presetting the time difference (t) between the time instant of starting theback lifting of the back-support portion 3a and the time instant of starting the knee liftingof the knee bottom section, and the angle setting switch Sa for presetting the knee liftingangle a (time T) are operated for re-presetting the time difference (t) and the knee liftingangle a respectively, and the time difference and the knee lifting angle are stored in thestoring means 9, then back lifting can be carried out effectively according to thecoordinative action pattern newly stored in the storing means 9.
• For example, if the head lifting switch Sw1 on thecontrol panel 6 is operated with thebase structure 3 kept lying flat, to apply an action command for starting the back lifting,action power is at first supplied to themotor 8b functioning as a directly acting drivemechanism of the knee lifting mechanism, to displace the knee lifting link, for incliningthe leg-support portion 3b. Then, after lapse of time t, the back lifting motor is turned onto supply action power to themotor 8a functioning as a directly acting drive mechanismof the back lifting mechanism, to displace the back lifting link, for inclining theback-support portion 3a. Then, if the knee lifting angle a of the knee liftingbottomsection 3b reaches the preset angle, theknee lifting motor 8b is turned off, and is turnedon for reverse rotation. At this moment, the electric power for starting the reverserotation is given to theknee lifting motor 8b, to lower the leg-support portion 3b.
• The adjustingaction control system 4 of this invention also allows a bottom coordinativeaction pattern to be preset also for the gatch action with forward body sliding and feelingsof abdominal compression reduced. Also in this case, since the knee lifting angle a atwhich the pressure is felt is different from subject to subject, the angle setting switch Sa for adjusting the knee lifting angle a on thecontrol panel 6 is preset at a desired kneelifting angle. Furthermore, the time difference (t) between the time instant of starting theaction of the back-support portion and the time instant of starting the action of theleg-support portion is preset by means of the time difference setting switch St.
• The maximum back lifting angle of the back-support portion 3a is limited in relation withthe knee lifting angle a of the leg-support portion 3b (for example, 90° or more).
• If the back lifting knee lifting coordinative switch Sw5 on thecontrol panel 6 is operatedto apply an action command for carrying out the gatch action, at first action power issupplied to themotor 8b functioning as a directly acting drive mechanism of the kneelifting mechanism, to displace the knee lifting link, for inclining the leg-support portion3b. Then, after lapse of time t, the back lifting motor is turned on to supply action powerto themotor 8a functioning as a directly acting drive mechanism of the back liftingmechanism, to displace the back lifting link, for inclining the back-support portion 3a.
• Then, after lapse of the predetermined time period (T) when the knee lifting angle a of theleg-support portion 3b reaches the preset angle, the knee lifting motor is turned off, tostop the leg-support portion 3b, for keeping it inclined at the angle (the dotted line of Fig.3).
• The back-support portion 3a can be inclined until the angle between the back-supportportion 3a and the leg-support portion 3b does not become smaller than 90°.
• The preferred embodiments of the lifting and lowering pattern are described below inmore detail in reference to figs.4-9.
• Figure 4 shows a state where all thesupport portions 3a, 3b and 3c are kept down to lieflat in a non-raised position, and in this state, a person such as a patient lies in an ordinarysupine position. To let the lying subject get up by lifting his/her back portion from thisstate, control switches are operated to issue commands to that effect to the means forcontrolling the lifting mechanisms.
• In this embodiment, the control means receiving a first one of the commands actuates firstthe lifting mechanism of the leg-support portion 3b as shown in Figure 5, to start liftingthe leg-support portion 3b only. The time instant when the lifting of the leg-supportportion 3b is started is t = 0 in Figure 3.
• Then, receiving the subsequent one of said commands, the control means starts lifting theback-support portion 3a at the time instant (t = t) suitably later than the time instant whenthe lifting of the leg-support portion 3b is started, and thereafter as shown in Fig. 6, boththe back-support portion 3a and the leg-support portion 3b are further lifted.
• As described above, in this embodiment, for pivotally rotating and lifting theback-support portion 3a from a flat state where all the support portions are kept down tolie flat, first the lifting of the leg-support portion 3b is started. Since the leg-supportportion 3b is lifted, the leg-support portion 3b supports the position of the waist of thesubject lying thereon, and therefore even if the lifting of the back-support portion is started in this state to gradually make the back-support portion steeply inclined, thesubject lying thereon is prevented from sliding forward due to pressure form theback-support means pressing on his/her back.
• If the lifting of the back-support portion 3a and the lifting of the leg-support portion 3bare continued further from the state of Fig. 3 without control, the angle formed betweenthe back-support portion 3a and the leg-support portion 3b becomes gradually smallerand gradually compresses the abdominal region of the subject lying thereon, finallyleading to feelings of discomfort to the subject.
• However, in the present invention, the lifting of the leg-support portion 3b is notcontinued further without control, but if the leg-support portion 3b reaches a preset liftedposition, it is not lifted any further.
• As shown in Figure 7, if the leg-support portion 3b reaches the preset highest position, thelifting of the leg-support portion 3b is stopped thereafter, and the lifting of theback-support portion 3a only is continued. In this coordinative operation, if themaximum angle of the leg-support portion 3b to the maximum angle of the back-supportportion 3a is preset, the angle formed between the back-support portion 3a and theleg-support portion 3b is prevented from becoming smaller than a certain angle.
• Therefore, the abdominal region of the subject is prevented from being graduallycompressed and causing feelings of discomfort to the subject.
• The leg-support portion 3 that reaches the preset highest position (time instant of t = T inFig. 3), hence the largest angle, can be controlled to maintain its position, but if it iscontrolled to decline from the highest position, a characteristic control action can beobtained as described below.
• The control action is that, as shown in Fig. 3, after the leg-support portion 3b reaches thepreset highest position (time instant of t = T in Figure 3), the control means acts to allowthe lifting of the back-support portion 3b continue, but acts to lower the leg-supportportion 3b. This control action is shown in Figure 5.
• In this control action, even if the leg-support portion 3b is lifted further to have a largerangle at a certain time instant before the back-support portion 3a reaches its highestposition, while the back-support portion 3a is further lifted to form a sharp angle, theangle of the leg-support portion 3b becomes gradually smaller. So, the angle formedbetween the back-support portion 3a and the leg-support portion 3b is prevented frombecoming smaller than a certain angle.
• Therefore, in this control action, the effect of the leg-support portion 3b having a largerangle positively prevents the lifting of the back-support portion 3a pressing on the back ofthe subject lying thereon and causing the subject to slide forward, and the abdominalregion of the lying person is prevented from becoming gradually compressed between theback-support portion 3a and the leg-support portion 3b resulting in discomfort to thesubject.
• The position to be reached by the leg-support portion 3b lowered from its preset highestposition can be suitably preset, depending on various conditions. In the example shownin Fig. 9 and by the solid line of Fig. 3, the leg-support portion 3b is lowered to be flat ina non-raised position.
• Next, as a first method of detecting the time instant when the lifting of the back-supportportion 3a is started (t = t) later than the time instant when the lifting of the leg-supportportion 3b is started (t = 0), and/or the time instant when the leg-support portion 3breaches its highest position (t = T), to ensure that the control means can carry out theabove-mentioned control action, the time elapsed from the time instant when the lifting ofthe leg-support portion 3b is started can be referred to for detecting said time instant.
• In the case where the capacities of the drive sources such as motors for actuating thelifting mechanisms of the back-support portion 3a and the leg-support portion 3b aresufficiently larger than the forces necessary for lifting the back-support portion 3a and theleg-support portion 3b on which the load of the lying person acts, or in the case where theload is constant, there is a constant correlation between the time elapsed after the timeinstant of actuating a lifting mechanism and the position of the corresponding liftedbottom section 3a or 1b. So, the elapsed time provides a simple method by which tocarry out the above-mentioned control action in response to the lifted position of thesupport portion 3a or 1b.
• Therefore, in this case, if the values of T1 and T2 in the control means can be altered, it ispossible to carry out a control action which is suitable for various conditions.
• As a second method of detecting the time instant when the lifting of the back-supportportion 3a is started (t = t) later than the time instant when the lifting of the leg-supportportion 3b is started (t = 0), and/or the time instant when the leg-support portion 3breaches its highest position (t = T), to ensure that the control means can carry out theabove-mentioned control action, a position detecting means such as an angle sensor canbe installed for the leg-support portion 3b, for detecting the position. The positiondetecting means for the leg-support portion 3b can be installed at any suitable place, forexample, at the leg-support portion itself, at the lifting mechanism or at the drive sourcesuch as a motor.
• Also in this case, if arrangement is made to ensure that the respective positions can bepreset, an adequate control action suitable for various conditions, such as the subject lyingon the base structure can be carried out.
• The control action of the back-support portion 3a and the leg-support portion 3b to whichthis invention is applied has been described as an action in the case where theback-support portion is pivotally rotated and lifted to an inclined position from anon-raised position. The action in the case where the support portions are lowered froman inclined position where the back-support portion is pivotally rotated and lifted, to anon-raised position, is reverse to the action explained for the case of raising the supportportions and so no additional explanation is necessary.
• Alternatively, in a further embodiment, the action in the case where the support portionsare lowered from a raised position where the back-support portion is pivotally rotated and lifted, to a non-raised position may be different from the reverse action to the actionexplained for the case of lifting.
• Furthermore, in the action for lowering, since the leg-support portion lifted to a certainposition or the highest position is lowered thereafter, a similar action occurs when theleg-support portion is lowered.
• Thus the subject is prevented from sliding forward, and when the entire base structurebecomes flat, the subject lying on the bottom is not slideably displaced. Thus the subjectis returned to a supine position without undue effort on the part of a care-giver.
• As described above, this invention can exhibit the following effects:
     When the support portions of a base structure for a bed or the like are adjusted todesired positions, they may be adjusted according to a desired adjusting action pattern.Thus, the support portions can be adjusted to suit the subject lying thereon with lessimposition on the subject.
     When the lifting of the back-support portion and the lifting of the leg-supportportion of a bed or the like are adjusted, the adjustment can be carried out according acoordinative action pattern suitable for the subject lying thereon. Thus, the lifting andlowering of the support portions can be adjusted with less imposition on the body of thesubject.
     The time difference between the time instant of starting the knee lifting of theleg-support portion and the time instant of starting the back lifting of the back bottomsection, and the knee lifting angle of the leg-support portion (knee lifting time period),can be preset, to easily and newly preset a coordinative action pattern.

Claims (5)

1. An adjusting action control system for a base structure for a bed or the likecharacterized in that when the support portions of the base structure are adjusted todesired positions, an adjusting action pattern can be preset to act until the support portionsreach the desired positions.
2. An adjusting action control system for a base structure for a bed or the like,characterized in that when a back-support portion of the base structure is lifted andlowered, a coordinative action pattern can be preset for the back lifting and lowering andaccompanying knee lifting and lowering of a subject lying thereon, until a back liftingangle of the back-support portion is reached.
3. An adjusting action control system for a base structure for a bed or the like,characterized in that when the lifting of the back-support portion and the lifting of theleg-support portion of the base structure are adjusted, a coordinative action pattern can bepreset to act until the desired positions of the support portions are reached.
4. An adjusting action control system according to Claim 2, wherein the timedifference between the time instant of starting the knee lifting of the leg-support portionand the time instant of starting the back lifting of the back-support portion, and a kneelifting time period of the leg-support portion, are preset in a coordinative action patternfor the back lifting of the back-support portion, wherein the knee lifting of the leg-supportportion is started first; subsequently after lapse of said preset time difference, the back lifting of the back-support portion is started; and after lapse of said preset knee liftingtime period of the leg-support portion, the knee lifting of the leg-support portion isstopped and then the knee lowering of the leg-support portion is started, while the backlifting of the back-support portion is continued until a desired back lifting angle isreached.
5. An adjusting action control system according to Claim 3, wherein the timedifference between the time instant of starting the knee lifting of the leg-support portionand the time instant of starting the back lifting of the back-support portion, and a kneelifting angle of the leg-support portion, are preset in a coordinative action pattern foradjusting the back lifting and knee lifting of the respective support portions, wherein thelifting of the leg-support portion is started first; subsequently after lapse of said presettime difference, the back lifting of the back-support portion is started; and if theleg-support portion reaches the preset knee lifting angle, the knee lifting of theleg-support portion is stopped, while the back lifting of the back-support portion iscontinued until a predetermined back lifting angle is reached.

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